330 



TUMORS. 



called homologous rhabdomyomata. But genuine Tieterologous rhabdomyo- 

 mata are, in almost all cases thus far recorded, confined to the genito- 

 urinary organs, kidney, ovary, and testicles. The writer has described 

 an exceptional case of rhabdomyoma occurring in the parotid gland. ' 



These tumors, when not associated with other and malignant tumors, 

 are benign and are of much greater theoretical than practical interest. 



NEUROMA. 



FIG. 175. NEUROMA GANGLIONIFORME. 

 Section from a tumor of the adrenal. 



A true neuroma is a tumor containing new-formed nerve tissue. Such 

 tumors are comparatively rare. Tumors developed in the connective 



tissue of nerves and composed 



V 



usually of fibrous or mucous 

 tissue are common, and are fre- 

 quently called neuromata, but 

 they should be called fibromata 

 orrnyomata, etc., of the nerves, 

 or false neuromata. The true 

 neuromata are of two kinds, 

 ganglionic or cellular neuromata 

 and fibrillar neuromata, depend- 

 ing upon the character of nerve 

 tissue which they contain. 

 The gangliouic neuromata 

 neuroma ganglioniforme in 



which new-formed nerve cells are present (Fig. 175), are found asso- 

 ciated with other structures in certain of the teratomata in the ovaries, 

 testicles, and in the sacral region ; they also occur in the gray matter of 

 the brain. They have been found in the adrenals. 



The fibrillar neuromata are, according to Virchow, of two kinds, mye- 

 linic and amyelinic, depending upon whether the nerve fibres which they 

 contain are medullated or not. The neuroma myelinicum is the more com- 

 mon and the best understood. The medullated nerve fibres in these 

 tumors are associated with fibrillar connective tissue, and are usually 

 curled and intertwined in a most intricate manner. They are either sin- 

 gle or multiple on the peripheral nerves. They may occur in consider- 

 able numbers as nodular tumors on the branches of a single nerve trunk, 

 or they may form an irregular, diffuse, nodulated enlargement of the 

 nerve branches plexiform neuroma. These neuromata may or may not 

 be painful. They not infrequently form at the cut ends of the nerves 

 in amputation stumps. They are benign tumors, never forming metas- 



The false neuromata are myxomata, or fibromata (Fig. 176), or some- 

 times myxo-sarcomata of the nerve sheaths or intrafascicular connective 

 tissue, and may be single or multiple. In the latter case they may affect 

 th? branches of a single nerve trunk (Fig. 177), or they may be found 



'American Journal of the Medical Sciences, vol. Ixxxv., p. 438, 1883. For later 

 bibliography consult lldbinrj, Centralbl. f. Path., Bd. ix., p. 433, 1898. 



